Gearing for rotating concentric shafts in opposite directions



y 2, E. c. HATCHER 2,347,906

GEARING F OR ROTATING CONCENTRIC SHAFTSIN OPPOSITE DIRECTIONS Fil'ed Sept. 9, 1942- 2 Sheets-Sheet 2 17a 5 J26. 4. a WENT W M M 2 m Am, 0TT0R(VEY Patented May 2, 1944 UNITED S'i" TENT O'F'FlfiE (BEARING FGR ROTATING CONCENTRIC SHAFTS 1N OPPOSITE DIRECTIONS Application September 9, 1942, SerialNo. 457,793 In Great Britain September 11, 1941 1 Claim.

This invention relates to improvements in power transmission gearing and has for its object to provide a simple and compact gearing adapted for transmitting the drive from a single shaft to two concentric shafts to be driven in opposite directions. In an electric torpedo, for example, the power from a high speed motor must be transmitted by speed reduction gearing to the concentric shafts of two propellers which revolve in opposite directions for the propulsion of the torpedo. In such vessels, it is important that the gearing should occupy a minimum space and nevertheless be adapted for eflicient operation.

According to this invention a pinion on the driving shaft drives two intermediate pinions on lay shafts circularly displaced from one another around the common axis of two concentric driven shafts, the one intermediate pinion being driven directly by the driving pinion and the other through a reversing pinion, and each intermediate pinion being united with a respective associate pinion which is in mesh with a driven pinion on a respective one of the concentricshafts. The driven pinions of the concentric shafts can be spaced a short distance apart along the common axis and the gap thus formed accommodates peripheral portions of the intermediate pinions on the lay shafts, so that a very compact gearing results.

In order to enable the invention to be readily understood, reference is made to the accompanying drawings, wherein:

Figure 1 is a central longitudinal section of a gearing in accordance with these improvements as applied for the propulsion of a torpedo.

Figure 2 is a cross section taken on the line II-II of Figure 1.

Figure 3 is a detail section taken on the line IIIIII of Figure 2.

Figure 4 is a detail section taken on the line IV-IV of Figure 2.

Referring to Figure 1 of the drawings, a and b are concentric inner and outer hollow output shafts which are to be driven in opposite directions from the shaft c of a motor M, only an end fragment of the latter being seen in the drawings. The motor shaft is in driving connection, through a coupling d, with an input shaft e of the gearing, the shaft e having fixedly mounted upon it a driving pinion I. As will be seen from Figure 2, the pinion f, on the right hand side, is in mesh with a large intermediate pinion g keyed on a lay shaft h. The pinion f, on the left hand side, is in mesh with a reversing pinion a fixedly mounted on a shaft is, the reversing pinion 7 being in mesh with a large intermediate pinion g keyed on a second'lay shaft h As will be seen from Figure 4, the pinion g has secured to it, or formed in one with it, a small'intermediate pinion Z which is in mesh with a large pinion m keyed to the outer one 19 of the concentric shafts ab, as seen in Figure l. The lay shaft h is mounted at its ends in ball bearings nn in supporting walls hereinafter described. The intermediate pinion g and its lay shaft h are similar to the pinion g and lay shaft h the latter lay shaft h being mounted in bearings similar to the bearings 'nn of the lay shaft h The intermediate pinion g has formed in one with it, or has secured to it, a small pinion 1, indicated by chain line circles in Figure 2 only. However, if a section, similar to Figure 4, were taken on the shaft 72., the pinion Z would be seen on the left hand side of the pinion g, whereas the pinion Z is on the right hand side of the pinion g in Figure 4. The pinion Z meshes with a large pinion o keyed on the inner one a of the concentric shafts ab. The output pinions o and m are spaced apart, as seen in Figure 1, and the input pinion f is disposed opposite the gap as between them. The intermediate pinions gg extend into this gap, which accounts for the pinion i being on the right hand side of the pinion g for meshing with the pinion m and the pinion Z being on the left hand side of the pinion g for meshing with the pinion o. It will thus be apparent that the shafts a and b are driven from the motor shaft 0 at equal speeds, the shaft a being driven oppositely to the shaft b owing to the introduction of the reversing pinion :i into its driving train.

Referring to Figure 3 it will be seen that the shaft k of the reversingpinion :i is borne by ball bearings pp in the supporting walls aforesaid and that the shaft is extended through the right hand wall. The extension k of the shaft it serves for the coupling up of the shaft of an auxiliary machine which may be contained in a casing :1, Figure 1.

In the example illustrated in Figure 1, the gearing is applied for the driving of tandem propellers rr of a torpedo, the skin or hull of which is marked t. The propeller r is fixedly mounted on a solid tail shaft s which is connected by a coupling a with the shaft a. The propeller r is fixedly mounted on a hollow concentric tail shaft s which is connected by a coupling 11. with the shaft 2). The hollow shaft .9 is supported by a stern bearing '0 in a sleeve w mounted in a conical support y fixed in the stern end of the torpedo. A bearing 2 for the shaft s is provided within the hub of the propeller r Forward, a ball bearing I is provided between the shafts a and b and a ball bearing 2 between the shaft b and a cylindrical support 3 rigidly attached to a strong plate 4 which is bolted to a bulkhead-5 of the torpedo. A box 6 enclosing the gearing is bolted to the plate 4 and the front wall of the box 6 together with the plate 4 provide the supporting walls for the bearings nn and pp of the shafts hh and k hereinbefore described with reference to Figures 4 and 3. A further ball bearing 1 for the shaft b is provided in the plate 4 adjacent to the hub of the output gear m. A further ball bearing 8 is provided in the front wall of the box b for the forward end of the shaft a, this bearing being adjacent to the hub of the output gear 0. An intermediate ball bearing 9 for the inner shaft a may be provided in the cupped boss of the pinion m. Finally, the shaft e is provided with ball bearings l0 and II in the plate 4 and front wall of the gear box 6 respectively. The two large output pinions m and o are strongly supported by the adjacent bearings land 8 and a spacing sleeve [2 is inserted between their hubs to maintain the correct gap a: between them.

Viewing the gearing in end elevation, as in Figur 2, and regarding the pinion m as a clock dial, the shaft h'of the pinions g and l is disposed at about four oclock, so that the opinion 9 can mesh with the driving pinion f the shaft e of which is disposed vertically beneath the shaft a. The shaft h of the pinions g and l is disposed at about nine oclock so that it is possible to interpose the reversing pinion a between the pinion g and the driving pinion f. A very compact gearing is thus provided which is enclosed by the box 6, the latter, as seen in end elevation, being somewhat elliptical and with the major axis tilted from the horizontal. This box 6 is well within the perimeter of the cylindrical body t of a torpedo.

The transmission gearing hereinbefore described is applicable for other purposes than the one described by way of example. For instantce, it may be employed for the driving of counterrunm'ng aircraft propellers. In this case the improved'transmission gearing enables any desired speed ratio to be provided between the prime mover and the propeller shafts without the necessity for incorporating an additional reducing gear such as is necessary when bevel reversing gear is used for such installations.

I claim:

Power transmission gearing between a single driving shaft and concentric driven shafts rotatable in opposite directions, comprising an input pinion on the driving shaft, a reversing pinion in mesh with said input pinion, output gears on respective driven shaftssaid output gears being spaced apart to provide a gap between them, two intermediate gears circularly spaced from one another around the common axis of the two concentric driven shafts and disposed each with a portion of its peripherywithin said gap between the output gears, one intermediate gear meshing with the driving pinion and the other intermediate gear meshing with the reversing pinion, and two reduction gears each united with a respective intermediate gear and in mesh with a respective output gear.

ERNEST CHARLES HATCHER. 

